It is routine practice for aftercare clinics to treat chronic schizophrenic patients in the community with maintenance antipsychotic medication. While the efficacy of these drugs in preventing relapse has been documented, their serious undesirable side effects, especially tardive dyskinesia, have been causing increasing concern. Studies have shown that for many stable outpatients the actions of these medications are prophylactic only, i.e., they do not reduce symptoms or improve functioning, but do help to prevent relapse. Thus, the possibility exists that stable outpatients may remain off medication and receive it only during prodromal phases of relapse (intermittent medication). This study attempts to evaluate the relative efficacy of intermittent drug administration compared with maintenance medication. One hundred eighty chronic schizophrenic outpatients will be randomly assigned in a double blind fashion to either intermittent or maintenance drug therapy. All patients will be engaged in weekly group therapy. The differential effectiveness of the two drug treatment programs over a two-year period will be determined by evaluating patients cross-sectionally in terms of major dimensions of psychopathology, role functioning, drug side effects, relapse and rehospitalization rates. Positive and negative effects on families will also be evaluated cross-sectionally. Efforts will be made to evaluate the relative risk-benefit ratio of the two programs. Finally, an attempt will be made to characterize those who need maintenance medication and those who do well on intermittent medication.